Hello, I'm Alicia. Thanks for your question. I'm happy to help you today.
Intrusive homosexual thoughts are not necessarily something to be alarmed about, and you'd be surprised to hear how common they are.
They are sometimes a sign of OCD (obsessive-compulsive disorder, a type of anxiety disorder), and Remeron is often used to treat OCD, but it can take some time for it to be effective. Normally, you'd start to see some benefit by now, but you might need to give it a little longer to fully take action.
If you love your wife and you enjoy sex and being intimate with her, then chances are pretty high that you're not gay, if that's what you're worried about.
You might find this article on homosexual obsessive-compulsive disorder informative: http://www.brainphysics.com/hocd.php
It's basically a subtype of OCD where straight people begin to develop an anxiety over possibly being homosexual - even though they aren't. So you might feel like you need to constantly remind yourself that you're not gay, or you might have worrisome thoughts like, what if I am gay? But it doesn't sound like this is the case in your situation. So I would try to relax, realize that it's most likely an anxiety reaction - and discuss it with the doctor who prescribed the Remeron, if it persists and you're not feeling any change within the next few weeks.
I hope that helps. Please let me know if you have any additional questions. Best of luck.